The slow sand filter method has been used for centuries to treat water. It's so effective that the World Health Organization has given it its stamp of approval: "Under suitable circumstances, slow sand filtration may be not ...

More than 70 years ago two palaeontologists named Robert Broom and John Robinson discovered a skull at the Sterkfontein Caves near Johannesburg. They nicknamed the skull, which is believed to be about 2.5 million years old, ...